While fitting the average spectra for both epochs using best fit model (i.e., TBabs\(\times \) (diskbb+relxilllpCp)), we fixed the value for the outer radius of the accretion disk at 400 r\(_{g}\) , where r\(_{g}\)  is the gravitational radius (r\(_{g} \equiv \)  GM/c\(^{2}\) ). We simultaneously fitted for a\(^{*}\)  and R\(_{in}\)  but those two parameters are degenerate, and the effective inner accretion disk radius is controlled by both a\(^{*}\)  and the disk inclination angle. In the case of a non-rotating black hole (a\(^{*}\)  \(\approx \)  0), R\(_{ISCO} \equiv \)  6r\(_{g}\) . However, in the case of a Kerr black hole, considering the co-rotating case where the accretion disk is rotating in a direction same as the compact object, R\(_{ISCO} \equiv \)  r\(_{g}\)  [1]}, [2]}. During the spectral fitting for both E1 and E2, the spin parameter (a\(^{*}\) ) approached the hard upper limit of 0.998. Therefore, we have frozen the value of a\(^{*}\)  at 0.998 and kept R\(_{in}\)  free to vary. For a black hole of a\(^{*}\)  \(\approx \)  0.998, R\(_{ISCO}\)  \(\approx \)  1.24 r\(_{g}\)  [1]}, [2]}.
